Demented subjects are identified by a 2-phase evaluation: administration of the screening test as part of the-regular biennial examination, coupled with neurological and neuropsychological evaluations of participants who fail the screening test. A second group of dementia cases will be identified from among recently deceased study participants based on: (a) poor performance on neuropsychological tests administered approximately 5 years ago, (b) review of medical records, and (c) telephone interviews with a surviving family member. Continuation of this project has as its major goals: (1) longitudinal observation of persons previously identified as demented, (a) to confirm the diagnosis, and (b) to develop a better understanding of common patterns of progression; and (2) identifying new dementia cases, (a) to increase the power of other studies, and (b) to define incidence rates more accurately.